The ingress of moisture into an integrated circuit (IC) chip can have a negative impact on the performance and reliability of circuitry aboard the chip. When moisture ingresses into the active chip circuitry, both the performance and reliability of IC chip significantly degrades. Severe moisture penetration can cause significant failures in the operation of the IC chip.
One method utilized today for detecting moisture in integrated circuits is a gas detection operation, which is performed during the manufacturing test and packaging stage of the IC fabrication process. However, this gas detection operation uses off-chip mechanisms and, thus, it does not provide a on-chip moisture detection scheme for the IC when it is installed in a finished product and operating in the field. During the lifetime of an IC chip, the package may crack because of, for example, severe temperature changes and other mechanical stress factors that can cause the chip moisture seal to break. If the chip seal breaks, moisture ingression into the chip may occur, which can result in IC chip malfunction and/or failure.
This may be especially true for large packaged integrated circuits used in severe temperature environments, such as IC chips for automobile, aircraft, and spacecraft applications. Additionally, because of advances in IC technology there may be increased current leakage and increased integration density of the circuits and, thus, much heat may be generated in an integrated circuit system. In particular, the temperature of the IC package may be ramped from room temperature to higher than 100° C. The large swing in temperature may cause tiny cracks in the IC package and in the die cover layer. These cracks may allow moisture invasion that leads to degradation of the IC chip performance and reliability.